【摘要】 研究了中药活性成分香荆芥酚(Carvacrol)的荧光光谱和吸收光谱,依据光谱数据测量了香荆芥酚的电离常数和荧光量子产率。在pH<2.0时,香荆芥酚的荧光随溶液pH增大而增强;在pH 2.0~8.0范围内,香荆芥酚有稳定的强荧光,最大激发波长为278 nm,最大发射波长为306 nm;pH>8.0时荧光强度随pH的增大而减弱。根据吸光度随pH的变化,测得香荆芥酚的电离常数pKa=10.44±0.06;根据荧光强度随pH的变化,测得香荆芥酚的电离常数pKa=10.40±0.04。将甲醇加入香荆芥酚的水溶液可使其荧光显著增强。以L-色氨酸为参比,测得香荆芥酚水溶液在激发波长278 nm处的荧光量子产率为0.121;在甲醇体积分数为80%溶液中的荧光量子产率为0.324。更多还原

【Abstract】 Fluorescence spectra and absorption spectra of carvacrol,an active component of Chinese herbal medicines,have been studied.The ionization constant and fluorescence quantum yield of carvacrol were measured according to spectral data.Under the condition of pH<2.0,fluorescence intensity of carvacrol increases with the increase in pH value.In the range of pH 2.0~8.0,carvacrol gives a strong and steady fluorescence with maximum excitation wavelength 278 nm and emission wavelength 306 nm.When pH>8.0,the fluorescence intensity decreases with the increase in pH value.Ionization constant of carvacrol was measured to be pKa=10.44±0.06 using a pH-absorbance method;and pKa=10.40±0.04 using a pH-fluorescence method.Fluorescence intensity of carvacrol was remarkably enhanced when methanol was added into its aqueous solution.Using L-tryptophane as a reference,the fluorescence quantum yield of carvacrol aqueous solution was measured to be 0.121 at excitation wavelength 278 nm;while in a solution containing 80% methanol,the quantum yield was measured to be 0.324.更多还原